They showed a graphic on the official definition of a flagrant 1/2. In there it said something about deceiving the ref into believing they were fouled (e.g., flopping or exaggerating/acting).
Since they made this so-called "flop" rule, I've seen maybe 3-5 total calls and they were flop "warnings". I have not seen any flop flagrants/technicals issued. Granted I can't possibly watch every single NCAA game, but at least in the ones I've watched with plenty of "acting" and flopping, it's never been called. And in most cases, especially in a UK game, we are always the team called for a foul when the other team flops/flails/overacts.